From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.xortex.at ([95.130.251.167]:39998 "EHLO mail1.xortex.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932140AbbLNK30 convert rfc822-to-8bit (ORCPT ); Mon, 14 Dec 2015 05:29:26 -0500 From: =?Windows-1252?Q?Georg_Sch=F6nberger?= To: Christoph Hellwig , Martin Steigerwald CC: Jens Axboe , Jeff Moyer , Linux FS-Devel , Linux Block mailing list , XFS mailing list Subject: Re: XFS and nobarrier with SSDs Date: Mon, 14 Dec 2015 10:18:54 +0000 Message-ID: <566E978E.2070502@xortex.com> References: <3496214.YTSKClH6pV@merkaba> <566E6524.6070401@xortex.com> <3911767.qVqsL1TcMv@merkaba> <20151214095823.GA30662@infradead.org> In-Reply-To: <20151214095823.GA30662@infradead.org> Content-Language: de-DE Content-Type: text/plain; charset="Windows-1252" Content-ID: <42159881-d2be-49c1-b0a6-14e54e2c0cfd> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 2015-12-14 10:58, Christoph Hellwig wrote: > On Mon, Dec 14, 2015 at 09:38:56AM +0100, Martin Steigerwald wrote: >> Is it safe to use XFS (or any other filesystem) on enterprise SSDs with Power >> Loss Protection (PLP), i.e. some capacitor to provide for enough electricity >> to write out all data in DRAM to flash after a power loss, with a reordering >> I/O scheduler like CFQ? > If the device does not need cache flushes it should not report requiring > flushes, in which case nobarrier will be a noop. OK - that would also mean that mounting with nobarrier should not make a performance difference. > Or to phrase it > differently: If nobarrier makes a difference skipping it is not safe. I do not fully understand that sentence, what do you mean by "makes a difference" and "skipping is not safe"? -Georg